Telegraphy



(No Model.) 2 Sheets-Sheet 1.

T. A. EDISON TBLEGRAPHY.

No. 422,072. Patented Feb. 25, 1890.

2 Sheets-Sheet 2.

(No Model.)

T. A. EDISON. TELEGRAPHY.

Patented Feb. 25, 1890.

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UNITED STATES PATENT OFFICE,

THOMAS A. EDISON, OF MENLO PARK, NEV JERSEY.

TELEG RAPHY.

SPECIFICATION forming part of Letters Patent No. 422,072, dated February25, 1890.

Application filed October 23, 1885. Serial No.180,689. (No model.)

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, of Menlo Park, in the county ofMiddlesex and State of New Jersey, have invented a new and usefulImprovement'in Telegraphy, (Case No. 653,) of which the following is aspecification.

The ordinary systems for duplex and quadceived simultaneously andwithout interference. This I accomplish by providing such lines with myinduction apparatus described in employing transmitters and receivers ofinduction impulses, and hereinafter referred to as induction apparatus,such apparatus being patents issued to me,numbered 333,289 and 333,290,a set of such apparatus being located in the main line at each terminaland way station. The artificial lines are provided each with one or moreelectro-magnets having an inductive capacity equal to the magnets andinduction-coils of the induction sets, in order to preserve the balancenecessary for the proper operation of the duplex or quadruplexapparatus. The relays of the duplex or quadruplex apparatus prove toosluggish in their action to respond to the rapid vibrations produced bythe induction-transmitters, and hence the duplex or quadruplex transmission will not be interfered with.

Since a duplex or quadruplex line is never open, there does not existthe necessity for providing; condenser-shunts around keys in order topreserve the continuity of the circuit for the induction signals, aspointed out in the applications referred to; but I have found thatspecial means are desirable or necessary to prevent false sounds in thediaphragm receivers of the induction apparatus, due to the responding ofsuch receivers to the extra vibrations produced by the duplex orquadruplex transmitting-instruments, and caused by the vibration of thecontacts. This difficulty is especially present when the inductionapparatus is used on quadruplex lines, the extra vibrations accompanyingthe reversals of current produced on such lines by the doublecurrenttransmitter-sot the quadruplex sets having a particularly disturbingeffect .upon' the diaphragm sounders. This disturbance can be avoided ifthe extra vibrations referred to can be neutralized and the impulses ofthe current-transmitters of the duplex or quadruplex apparatus beconverted into simple waves or waves with a less number of vibrationsthan are required to produce sound. This I accomplish by including inthe currenttransmitter circuit at each end of the duplex or quadruplexline, and before such line is divided at the junction of the main andartificial lines, an electro-n1agnet,and providinga condenser-shuntaround this electro-magnet and the transmitter-cont-acts. By thecombined action of the electro-magnet and condenser the oxtra vibrationscaused by the rebound. of the contacts are neutralized entirely, or to asufficient extent to prevent false signals in the diaphragm receivers ofthe induction sets. This device, when applied to duplex or quadruplexsets, prevents inductive disturbances in telephones connected withadjoining lines. This device is only claimed herein in combination withthe other novel features described, it being broadly covered by anotherapplication for patent'of even date herewith.

In the accompanying drawings, forming a part hereof, Figure 1. is aview, principally in diagram, showing the application of the inventionto a duplex line; Fig. 2, a similar view of a quadruplex line, one endof line being alone shown; and Fig. 3, an elevation from the rear sideof the diaphragm sounder and support with portions of the case removedto show working parts.

Referring more particularly to Fig. 1, L L represent the main line, andA A the artificial lines. B is the current transmitter of the duplexsets, and C the duplex relays. Three stations are shown 011 the-linetwoterminal stations S S and a way-station S The du plex sets are at theterminal stations, at which are also phonoplex sets located in orconnected with the main line, At each of the one or more waystations onthe line is also an in duction set located in the line. The induc- IOCtion sets have each a transmitter and receiver of the induction signals.The transmitter is an induction-coil I, having its secondary circuitdirectly in line, and having in its primary circuit a local battery aand a suitable circuit-controlling device I). The receiver is adiaphragm sounder R, located in a shunt around an electro-magnetD inline, this shunt including also a condenser 0. Each artificial line Ahas one or more electro-magnets E, equal in inductive capacity to thecoils and magnets of the induction sets in line. In the circuit of eachduplex-current transmitter B before that circuit divides into the mainand artificial lines is an electro-magnet F. A shunt-circuit 1 2 isformed around magnet F and transmitter B, which shunt includes acondenser F. These parts are for the purpose already explained. In Fig.2 the same parts are shown in connection with a quadruplex set, of whichT.T are the single and double current transmitters, and G H thenon-polarized and polarized relays. The shunt 1 2 is formed around thepoints of both transmitters. The induction sets transmit and receiveMorse signals by rapid induction impulses which do not affect the relaysof the duplex or quadruplex sets.

The diaphragm'sounder is shown in detail. in Fig. 3. It is -anelectro-motograph telephone-receiver mounted on the outer end of anarmI, which is pivoted at its inner end to a suitable support K. Thechalkcylinder of the motograph is on a spindle d, extending to the innerend of arm I, where it is connected by a speed-reducing gearing with anelectric motor M, all these parts beingmounted on arm I and turningtherewith. The chalk cylinder'of the motograph is keptin constantrotation by the electric motor, so that the instrument will be ready atall times to respond ploying transmitters and receivers of induc tionimpulses located in said mainline for permitting single transmissionback and forth over said line without interference with the duplex orquadruplex transmission, substantially as set forth.

2. The combination, with duplex or quadruplex telegraph instruments andthe line therefor for duplex or quadruplex transmission' betweenterminal stations, of telegraphinstruments employing transmitters andreceivers of induction impulses located in said line at terminal and waystations, substantially as and for the purposes set forth.

3. The combination, with duplex or quadruplex telegraph instrumentsandthe main and artificial lines therefor, of telegraph-instrumentsemploying transmitters and receivers of induction impulses located inthe main line, and one or more balancing electro-magnets in eachartificial. line, substantiallyas set forth.

4. The combination, with duplex orquad- ;ruplex telegraph instrumentsandthe main line therefor, of telegraph-,instruments employingtransmitters and .receiversof induction impulses located in themain.line,.;an electro-magnet in each duplex orquadruplex transmittercircuit, and .a condenser,- shunt around such magnet and thetransmitter-contacts, substantially as set forth.

5. The combination, with duplex or..quadruplex telegraph instruments.and the main and artificial lines therefor, oftelegraph-instruments.employing transmitters. and receivers of inductionimpulses located in the main line, balancing electro-magnets intheartificial lines, a magnet in eachduplex .or-quadruplex transmittercircuit,.and ,a condensershuntaround each of such ,magnetsand thetransmitter contacts, substantially ;as set forth.

This specification signed and witnessed this 7th day of October, 1885.

/ THOS. AHEDISON.

Witnesses:

A. W. KIDDLE,

G..R0WLAND.

